Mercier Annie, Sun Zhao, Parrish Christopher C, Hamel Jean-François
Department of Ocean Sciences, Memorial University, St. John's, Newfoundland and Labrador, Canada.
Society for the Exploration and Valuing of the Environment (SEVE), Portugal Cove-St. Philips, Newfoundland and Labrador, Canada.
PLoS One. 2016 Apr 22;11(4):e0154051. doi: 10.1371/journal.pone.0154051. eCollection 2016.
Animals display diverse means of producing and provisioning offspring, from eggs to embryos and juveniles. While external development predominates, many forms of embryonic incubation have evolved, including placentation in mammals and a number of understudied variants in basal metazoans that could help understand evolutionary diversification. Here we studied the brooding sea anemone Aulactinia stella, using behavioural, morphological and biochemical indicators of offspring phenotype to characterize gestation and elucidate parental and sibling relationships. The pronounced variance in juvenile weight within broods was not strongly related to any of the typical external predictors (adult weight, clutch size, sampling date, environmental conditions). Lipid concentration was significantly higher in the tissues of the small juveniles than in those of large juveniles or adult, and fatty acid profiles tended to set small juveniles apart. Finally, intra-brood feeding on external resources was documented in larger juveniles. These results are consistent with ontogenetic shifts in nutrition, from vitellogenic provisioning to post-zygotic nourishment to a prenatal form of nursing upon acquisition of feeding organs, highlighting matrotrophic and conflict-driven mechanisms acting on offspring phenotype during gestation.
动物展示出从卵到胚胎及幼体等多种繁殖和养育后代的方式。虽然外部发育占主导，但多种胚胎孵化形式已经进化出来，包括哺乳动物的胎盘形成以及一些基础后生动物中尚未充分研究的变体，这些变体有助于理解进化多样化。在此，我们研究了孵育幼体的海葵星状海葵，利用后代表型的行为、形态和生化指标来表征妊娠期并阐明亲代与同胞关系。幼体群体中幼体体重的显著差异与任何典型的外部预测因素（成体体重、卵块大小、采样日期、环境条件）均无强烈关联。小幼体组织中的脂质浓度显著高于大幼体或成体组织中的脂质浓度，并且脂肪酸谱倾向于将小幼体区分开来。最后，在较大幼体中记录到了幼体群体内对外部资源的取食行为。这些结果与营养的个体发育转变一致，即从卵黄生成供应到合子后营养，再到获得摄食器官后产前形式的哺育，突出了妊娠期作用于后代表型的母源性营养和冲突驱动机制。
